fix: Improve error messages for unknown explainers and data loaders

Author: Felipedino

DashAI/back/units/explanation_artifacts.py

@@ -55,8 +55,8 @@ def build_explainer(scope: str, selected: dict, trained_model: Any) -> Any:
     except Exception as e:
         log.exception(e)
         raise JobError(
-            f"""Unable to find the {scope} explainer with name
-                            {explainer_name} in registry.""",
+            f"Unable to find the {scope} explainer with name "
+            f"{explainer_name} in registry.",
         ) from e
 
     try:

DashAI/back/units/load_datafile_dataset_unit.py

@@ -133,11 +133,15 @@ def execute(self, ctx: ExecutionContext) -> None:
 
         source = _resolve_source_file(work_dir, selected_file)
 
+        # Looked up among the readers specifically, not with the registry's
+        # global ``registry[name]``: that one walks every component type, so a
+        # metric or a model whose name happened to be passed here would be
+        # instantiated as if it could read a file instead of being rejected.
         dataloader_name = dataloader_config["component"]
-        registry = component_registry.registry.get("DataLoader", {})
-        if dataloader_name not in registry:
+        readers = component_registry.registry.get("DataLoader", {})
+        if dataloader_name not in readers:
             raise JobError(f"DataLoader '{dataloader_name}' not found in registry.")
-        dataloader = registry[dataloader_name]["class"]()
+        dataloader = readers[dataloader_name]["class"]()
 
         log.debug("Loading hub dataset from %s using %s", source, dataloader_name)
         ctx.put(

tests/back/api/test_explainer_job.py

@@ -503,8 +503,11 @@ def test_a_model_that_cannot_be_loaded_names_the_path(client, run_id):
 def test_an_unknown_explainer_name_is_reported_with_the_multiline_message(
     client, run_id
 ):
-    """The message is a triple-quoted f-string, so its newline and indentation
-    are literally part of the text the user sees. Pinned as-is."""
+    """One line, so it stays readable wherever it surfaces.
+
+    It used to be a triple-quoted f-string, which put a newline and the source
+    file's indentation literally inside the text the user reads.
+    """
     explainer_id = _create_global_explainer(
         client, run_id, explainer_name="NoSuchExplainer"
     )
@@ -513,8 +516,7 @@ def test_an_unknown_explainer_name_is_reported_with_the_multiline_message(
         ExplainerJob(explainer_id=explainer_id, explainer_scope="global").run()
 
     assert str(excinfo.value) == (
-        "Unable to find the global explainer with name\n"
-        "                            NoSuchExplainer in registry."
+        "Unable to find the global explainer with name NoSuchExplainer in registry."
     )
 
 

tests/back/units/test_dataset_ingest_units.py

@@ -489,3 +489,34 @@ def test_datafile_unit_has_its_own_wording_for_an_unknown_reader(
         )(ExecutionContext())
 
     assert str(excinfo.value) == "DataLoader 'NoSuchLoader' not found in registry."
+
+
+def test_datafile_unit_rejects_a_component_that_is_not_a_reader(
+    datafile_rows, csv_file, tmp_path
+):
+    """A registered component of some other kind is still not a reader.
+
+    The registry's ``registry[name]`` indexer searches every type at once, so
+    looking the name up that way would find, say, a metric and call it as if it
+    could parse a file. The lookup is deliberately scoped to the readers.
+    """
+    from DashAI.back.core.enums.status import DatafileStatus
+    from DashAI.back.dataloaders.classes.csv_dataloader import CSVDataLoader
+    from DashAI.back.dependencies.registry import ComponentRegistry
+    from DashAI.back.metrics.classification.accuracy import Accuracy
+
+    di["component_registry"] = ComponentRegistry(
+        initial_components=[CSVDataLoader, Accuracy]
+    )
+    datafile_rows[7] = _DatafileRow(str(tmp_path), DatafileStatus.READY)
+    try:
+        with pytest.raises(JobError) as excinfo:
+            LoadDatafileDatasetUnit(
+                dataloader={"component": "Accuracy", "params": {}},
+                datafile_id=7,
+                selected_file="data.csv",
+            )(ExecutionContext())
+    finally:
+        del di["component_registry"]
+
+    assert str(excinfo.value) == "DataLoader 'Accuracy' not found in registry."